a=0.09208;
b=1.003 ;
a=65.78;
b=0.226 ;
% a=12.18;
% b=0.6988 ;
sigma=0;
x=xsave2;
y=ysave2;
for i=1:1:size(x,2)
    sigma=sigma+(y(i)-a-b*x(i))*(y(i)-a-b*x(i));
end
sigma=sigma/(size(x,2)-2);
x_ave=mean(x);
lxx=0;
for i=1:1:size(x,2)
    lxx=lxx+(x(i)-x_ave)*(x(i)-x_ave);
end
t=b*sqrt(lxx)/sigma;